Condition sensitive method and apparatus for imaging a lithographic printing plate

Abstract

A platesetting method and apparatus provides for dimensional and/or exposure sensitivity changes in a printing plate to be imaged in a platesetter. A condition sensor senses the temperature of the plate prior to exposure so that a control unit can adjust the control commands to the scanning exposure mechanism of the platesetter in order to compensate for any thermal expansion or exposure sensitivity shifts. An image to be recorded onto the plate material has a standard size at a standard plate material temperature. When the plate material is at a non-standard temperature, as determined by the thermal sensor, a program, stored in memory, calculates a new image size based on the non-standard temperature and the thermal characteristics of the plate material which are also stored in memory. The imagesetter electronic controller then exposes an image having a size which will be the standard size when the plate material returns to the standard temperature.

I claim: 
     
       1. A method for producing an image on a receiving material, comprising the steps of: (a) sensing a condition of an image receiving material on which an image is to be formed by an imaging beam;   (b) adjusting the imaging beam according to the sensed condition of the image receiving material to compensate for a change in a condition sensitive characteristic of the image receiving material due to a difference between the sensed condition and a reference condition of the image receiving material; and   (c) forming the image on the image receiving material with the adjusted imaging beam.   
     
     
       2. The method according to claim 1, wherein: said step of forming the image on the image receiving material includes scanning the adjusted imaging beam on the image receiving material while modulating the adjusted imaging beam according to image data representing the image; and   the step of adjusting the imaging beam includes adjusting the exposure level of the imaging beam according to the sensed condition of the image receiving material to compensate for the change in the condition sensitive characteristic of the image receiving material.   
     
     
       3. The method according to claim 1, wherein: said step of forming the image on the image receiving material includes scanning the adjusted imaging beam on the image receiving material while modulating the adjusted imaging beam according to image data representing the image; and   the step of adjusting the imaging beam includes adjusting the modulation frequency of the imaging beam according to the sensed condition of the image receiving material to compensate for the change in the condition sensitive characteristic of the image receiving material.   
     
     
       4. The method according to claim 1, wherein the sensed condition is temperature and the condition sensitive characteristic is geometric size of the image receiving material. 
     
     
       5. The method according to claim 1, wherein the sensed condition is temperature and the condition sensitive characteristic is exposure sensitivity of the image receiving material. 
     
     
       6. The method according to claim 1, wherein the sensed condition is humidity and the condition sensitive characteristic is geometric size of the image receiving material. 
     
     
       7. The method according to claim 1, wherein the sensed condition is humidity and the condition sensitive characteristic is exposure sensitivity of the image receiving material. 
     
     
       8. A method for producing an image on an image receiving material, comprising the steps of: (a) sensing a temperature of an image receiving material on which an image is to be formed with an imaging beam;   (b) determining a size of said image to be formed on the image receiving material according to a coefficient of thermal expansion of said image receiving material and the sensed temperature;   (c) adjusting the imaging beam to correspond to said size; and   (d) forming said image on said image receiving material with the adjusted imaging beam.   
     
     
       9. The method according to claim 8, further comprising the step of repeating said steps to produce the image on multiple sheets of the image receiving material, each of said multiple sheets being of substantially the same size and having a substantially equal temperature, such that the image produced on each of said multiple sheets is of uniform size. 
     
     
       10. An apparatus for producing an image on a receiving material, comprising: a sensor for sensing a condition of an image receiving material on which an image is to be formed;   an imaging device for exposing the image receiving material to form the image thereon;   a controller for controlling the imaging device according to the sensed condition of the image receiving material to compensate for a change in a condition sensitive characteristic of the image receiving material due to a difference between the sensed condition and a reference condition of the image receiving material such that the image formed on the image receiving material corresponds to the changed condition sensitive characteristic of the image receiving material.   
     
     
       11. The apparatus according to claim 10, wherein: the sensed condition is a sensed temperature, the reference condition is a reference temperature and the condition sensitive characteristic is exposure sensitivity,   said imaging device includes a scanner for scanning an imaging beam on the image receiving material while modulating the imaging beam according to image data representing the image, and   said controller controls the imaging device to adjust the exposure level of the imaging beam according to the sensed temperature of the image receiving material to compensate for the change in the exposure sensitivity of the image receiving material due to the difference between the sensed temperature and the reference temperature of the image receiving material.   
     
     
       12. The apparatus according to claim 10, wherein: the sensed condition is a sensed temperature, the reference condition is a reference temperature and the condition sensitive characteristic is geometric size,   said imaging device includes a scanner for scanning an imaging beam on the image receiving material while modulating the imaging beam according to image data representing the image, and   said controller controls the imaging device to adjust the modulation frequency of the imaging beam according to the sensed temperature of the image receiving material to compensate for the change in the geometric size of the image receiving material due to the difference between the sensed temperature and the reference temperature of the image receiving material.   
     
     
       13. The apparatus according to claim 10, wherein the sensed condition is temperature and the condition sensitive characteristic is geometric size of the image receiving material. 
     
     
       14. The apparatus according to claim 10, wherein the sensed condition is temperature and the condition sensitive characteristic is exposure sensitivity of the image receiving material. 
     
     
       15. The apparatus according to claim 10, wherein the sensed condition is humidity and the condition sensitive characteristic is geometric size of the image receiving material. 
     
     
       16. The apparatus according to claim 10, wherein the sensed condition is humidity and the condition sensitive characteristic is exposure sensitivity of the image receiving material. 
     
     
       17. An apparatus for producing an image on an image receiving material from a digital image, comprising: (a) sensing means for sensing a temperature of the receiving material on which the image is to be formed;   (b) means for determining a temperature dependent size for said digital image according to a coefficient of thermal expansion of said image receiving material and the temperature sensed by said sensing means;   (c) means for adjusting the digital image to correspond to said temperature dependent size; and   (d) means for forming the image on the receiving material in accordance with the adjusted digital image.   
     
     
       18. The apparatus according to claim 10, wherein: the sensed condition is a sensed temperature, the reference condition is a reference temperature and the condition sensitive characteristic is geometric size,   said imaging device includes scanning means for scanning an imaging beam on the image receiving material while modulating the imaging beam according to image data representing the image, and   said controller controls the scanning means so as to adjust the scanning speed of the imaging beam according to the sensed temperature of the image receiving material to compensate for a change in the geometric size of the image receiving material due to the difference between the sensed temperature and the reference temperature of the image receiving material.   
     
     
       19. The method according to claim 1, wherein said step of forming image on the image receiving material includes: (a) scanning the imaging beam on the image receiving material while modulating the imaging beam according to digital image data representing the image; and   (b) adjusting a scanning speed of the imaging beam according to the sensed condition of the image receiving material to compensate for the change in the condition sensitive characteristic of the image receiving material.   
     
     
       20. The method according to claim 1, wherein said step of forming the image on the image receiving material includes: (a) scanning the imaging beam on the image receiving material while modulating the imaging beam according to digital image data representing the image; and   (b) adjusting a modulation frequency and a scan speed of the imaging beam according to the sensed condition of the image receiving material to compensate for the change in the condition sensitive characteristic of the image receiving material.   
     
     
       21. A method for producing an image on a receiving material, comprising the steps of: (a) sensing a condition effecting a condition sensitive characteristics of an image receiving material on which an image is to be formed by an imaging beam;   (b) adjusting only the imaging beam according to the sensed condition to compensate for a change in the condition sensitive characteristic of the image receiving material due to a difference between the sensed condition and a reference condition; and   (c) forming the image on the image receiving material with the adjusted imaging beam.   
     
     
       22. The method according to claim 21, wherein: said step of forming the image on the image receiving material includes scanning the adjusted imaging beam on the image receiving material while modulating the adjusted imaging beam according to the image data representing the image; and   the step of adjusting the imaging beam includes adjusting the exposure level of the imaging beam according to the sensed condition of the image receiving material to compensate for the change in the condition sensitive characteristic of the image receiving material.   
     
     
       23. The method according to claim 21, wherein: said step of forming the image on the image receiving material includes scanning the adjusted imaging beam on the image receiving material while modulating the adjusted imaging beam according to image data representing the image; and   the step of adjusting the imaging beam includes adjusting the modulation frequency of the imaging beam according to the sensed condition of the image receiving material to compensate for the change in the condition sensitive characteristic of the image receiving material.   
     
     
       24. The method according to claim 21, wherein the sensed condition is temperature. 
     
     
       25. The method according to claim 24, wherein the condition sensitive characteristic is one of exposure sensitivity of the image receiving material and geometric size of the image receiving material. 
     
     
       26. The method according to claim 21, wherein the condition sensitive characteristic is geometric size of the image receiving material. 
     
     
       27. The method according to claim 21, wherein the sensed condition is humidity and the condition sensitive characteristic is geometric size of the image receiving material. 
     
     
       28. The method according to claim 21, wherein the step of adjusting the imaging beam includes adjusting the imaging beam to one of a plurality of settings greater than two to compensate for the change in the condition sensitive characteristic of the image receiving material. 
     
     
       29. An apparatus for producing an image on a receiving material, comprising: a sensor for sensing a condition effecting a condition sensitive characteristic of an image receiving material on which an image is to be formed;   an imaging device for exposing the image receiving material with an imaging beam to form the image thereon;   a controller for controlling the imaging device to adjust only the imaging beam according to the sensed condition to compensate for the change in the condition sensitive characteristic of the image receiving material due to a difference between the sensed condition and a reference condition such that the image formed on the image receiving material corresponds to the changed condition sensitive characteristic of the image receiving material.   
     
     
       30. The apparatus according to claim 29, wherein the sensed condition is temperature. 
     
     
       31. The apparatus according to claim 29, wherein the condition sensitive characteristic is one of exposure sensitivity of the image receiving material and geometric size of the image receiving material. 
     
     
       32. The apparatus according to claim 29, wherein the condition sensitive characteristic is geometric size of the image receiving material. 
     
     
       33. The apparatus according to claim 29, wherein the sensed condition is humidity and the condition sensitive characteristic is geometric size of the image receiving material. 
     
     
       34. The apparatus according to claim 29, wherein the controller is configured to control the imaging device so as to adjust the imaging beam to one of a number of settings, the number being greater than two, to compensate for the change in the condition sensitive characteristic of the image receiving material. 
     
     
       35. An apparatus for producing an image on a receiving material, comprising: a sensor for sensing a condition effecting a geometric size of an image receiving material on which an image is to be formed;   an imaging device for exposing the image receiving material with an imaging beam to form the image thereon;   a controller for controlling the imaging device according to the sensed condition to compensate for the change in the geometric size of the image receiving material due to a difference between the sensed condition and a reference condition such that the image formed on the image receiving material corresponds to the changed geometric size of the image receiving material.   
     
     
       36. The apparatus according to claim 35, wherein the sensed condition is one of a temperature and a humidity.